Process for producing fluorosilicon polymers

Abstract

The invention comprises a method for producing fluorosilicone oil by reacting a fluorosilicone trimer with a triorganosilanol in the presence of an alkali silanolate. The polymer may be condensed to increase viscosity and decrease the silanol content of the polymer, and volatiles may be removed by stripping. The method provides a high yield of fluorosilicone oil of narrow viscosity ranges in an efficient reaction, and produces small amounts of waste.

What is claimed is:  
     
       1. A method for producing fluorosilicone polymers, comprising: 
       reacting an organic chain-stopping compound in the presence of a first alkali silanolate, with a fluorosilicone trimer of the formula:                    
        wherein  
       R 1  is a monovalent hydrocarbon of 1-8 atoms, R 2  is a perfluoroalkylethylene radical of 3-8 carbon atoms, forming a polymer solution containing a first polymer; and  
       adding a hexaorganosiloxane and a rearrangement catalyst to said polymer solution.  
     
     
       2. The method according to  claim 1 , wherein said organic chain-stopping compound is a triorganosilanol. 
     
     
       3. The method according to  claim 1 , wherein said organic chain-stopping compound is of the formula:                    
       wherein 
       R3 is a monovalent hydrocarbon radical of 1-8 carbon atoms, R2 is a perfluoroalkylethylene radical of 3-8 carbon atoms, and z is an integer of about 2 to 10.  
     
     
       4. The method according to  claim 1 , wherein said rearrangement catalyst is linear phosphonitrilic chloride. 
     
     
       5. The method according to  claim 2 , wherein said hexaorganodisiloxane is hexamethyldisiloxane.